There was one strobe-like tuner for Android years ago that seemed to be something other than a visual representation of a standard digital tuner.
My understanding of the way it worked is that it took the waveform over some set N/frequency time, converted it to a 1D horizontal line of black→white pixels, and then stacked subsequent lines to create a 2D image, with new lines being added at the top and moving down. In tune (or a multiple of the root frequency for the image), you'd see a series of vertical black and white bars; out of tune, these bars would slant to the left or right, and move over time.
This method was actually somewhat like a strobe tuner in mechanism, replacing the persistence-of-vision appearance of the bars moving with a spatial representation of the audio waveform moving in comparison to the reference frequency. Presumably, this could also have been done without the stacked 2D representation, but that doesn't seem to be what apps like iStroboSoft do, as the bars are far too clean and even. While the app didn't do it, harmonic partials could have been added by having multiple simultaneous 2D images, each with a different reference frequency.
Unfortunately, the app and its developer disappeared years ago, and while I might still have the apk somewhere. I haven't seen anything like it since.
I now recall that this was Pitchlab / Pitchlab Pro. The app still seems to work on Android 11, but isn't available through Google.
The last version's release notes, combined with the subsequent discontinuation and disappearance, suggest that there may have been patent problems that led to its demise.
My understanding of the way it worked is that it took the waveform over some set N/frequency time, converted it to a 1D horizontal line of black→white pixels, and then stacked subsequent lines to create a 2D image, with new lines being added at the top and moving down. In tune (or a multiple of the root frequency for the image), you'd see a series of vertical black and white bars; out of tune, these bars would slant to the left or right, and move over time.
This method was actually somewhat like a strobe tuner in mechanism, replacing the persistence-of-vision appearance of the bars moving with a spatial representation of the audio waveform moving in comparison to the reference frequency. Presumably, this could also have been done without the stacked 2D representation, but that doesn't seem to be what apps like iStroboSoft do, as the bars are far too clean and even. While the app didn't do it, harmonic partials could have been added by having multiple simultaneous 2D images, each with a different reference frequency.
Unfortunately, the app and its developer disappeared years ago, and while I might still have the apk somewhere. I haven't seen anything like it since.